Acid-Base Problems PDF

122 ACID-BASE PROBLEMS Hemoglobin Derivatives Determine the acid-base status in each of 1. Hemoglobin (Hb) breakdown products the following examples: ind ude porphyrins, bilirubin and 1....

122 ACID-BASE PROBLEMS Hemoglobin Derivatives Determine the acid-base status in each of 1. Hemoglobin (Hb) breakdown products the following examples: ind ude porphyrins, bilirubin and 1. urobilinogen pH= 7.24 pC02 = 44 LABORATORY ANALYSIS OF PORPHYRINS AND HC03=18 RELATED COMPOUNDS Answer: Metabolic Acidosis 1. Urines with large amounts of ( uncompensated); Phonetia and Carbo porphyrins sh ow a red or "port wine" are swinging down. pH< 7.35 color 2. 2. Chromatography (HPLC, ion- pH= 7.52 exchange) to separate. All porphyrins pC02 = 44 h ave a characteristic pink fluorescence HC03= 39 (can be quantitated using a UV spectrophotometer or flurometer) Answer: Metabolic Alkalosis ( uncompensated); Phonetia and Carbo 3. Watson-Schwartz test are swinging up. pH> 7.45 a. Porphobilinogen (PBG) will react with Ehrlich's reagent, p-dimethyl- 3. aminobenzaldehyde, to form r ed pH= 7.26 color pC02 = 56 b. Add chloroform to separate PBG HC03= 24 from interfering compounds including urobilinogen (UBG) Answer: Respiratory Acidosis ❖ Color in chloroform top layer= (uncompen sated); Phonetia and Paco UBG and other interfering are on the seesaw. pH< 7.35 compounds ❖ Color in aqueous bottom layer = 4. PBG pH= 7.52 pC02 = 28 LABORATORY ANALYSIS OF BILIRUBIN HC03= 21 1. Diazotization methods Answer: Partially compensated respiratory alkalosis. Phonetia and Paco are seesawing. Carbo joins Paco to compensate. Correlate Porpbyrin 5. Reaults with Disease pH= 7.39 (tiee Bematology cbapwr) pC02 = 25 HC03= 15 a. Classic method ❖ Bilirubin + diazotized sulfanili.c Answer: Completely compensated metabolic acidosis or completely acid ~ azobilirubin (purple) ❖ Total bilirubin (conjugated+ compen sated respiratory alkalosis. For unconjugated) reacts slowly with these situations, look at the pH. If it is diazo reagent on the low side of normal, choose ❖ Conjugated biliruhin (direct) acidosis. If it is on the high side of normal, choose alkalosis. In a like reacts rapidly with diazo reauent manner, completely compensated in water Jendrassik-Grof m:thod metabolic alkalosis cannot be uses caffeine-benzoate as accelerator distinguished from fully compensated c, Direct= conjugated= water soluble respiratory acidosis. The Phonetia, d. Indirect = unconjugated = r elatively Paco and Carbo story will work > 90% of the time in solving acid-base insoluble in water problems.  123 2. Direct Spectrophotometric method 3. Posthepatic ( obstructive) jaundice a. Newborns only; they Jack a. Conjugated and unconjugated interfering compounds bilirubin cannot be metabolized Rroperly; " back-up" into plasma 3. Sp ecimen collection and handling b. t urobilinogen (due to Mockage) a. Bilirubin is light sen sitive, ther efor e prevents conjugated hilirubin from sample should h e stored in d ark entering intestine to be broken (amber-colored) glass down into urobilinogen b. Lipemia - falsely ,t. r esults c. Stool may become clay colored c. Hemolysis - falsely tor~ results depending on hemoglobin & bilirubin concentration GENERAL INFORMATION 1. When unconjugated bilirubin is ,t., there will be a ;+.. in urine urobilinogen + (due to a.mount reabsorbed from intestine and filtered by kidney) 2. When conjugated hilirubin (wa ter soluble) is ,t. , it will appear in urine CONDITIONS 1. P re-hepatic jaundice (i.e. hemolytic anemia) a. ,t. red cell destruction ➔ + unconjugated bilirubin MA1ERNAL Af'O tEW80RN TESTING DURING PREGNANCY b. Liver function is normal; conjuga tion occurs at normal rate 1. Maternal Serum prenatal testing at 16 ➔ normal conjuga ted bilirubin weeks gestation and no bilirubin in urine a. Detection of n eural tube defects c. ,t. unconjugated bilirubin ➔ ,t. (such as spina hifida) urine urobilinogen ,t. alpha fctoprotcin (AFP) h. Detection of Down' s Svndrome 2. Hepatic jaundice (i. e. viral hepatitis, ❖ Triple (HCG, AFP, ~nconjugated cirrhosis) estriol) or Quad (add Inhihin A) a. ,t. unconjugated bilirubin, ,t. screen conjugated biliruhin and ,t. t AFP urobilinogen due to liver t estriol dysfunction ,t. H CG b. ,+.: conjugated hilirubin ➔ ,t. urine Quad: (,t. Inhibin A) biliruhin c. ,t. urine urobilinogen Bilirubin and Disedse states Plasma/Serum Urine DISEASE UNCONJUGATED CONJUGATED BILIRUBIN UROBILINOGEN BILIRUBIN BILIRUBIN Prehepatic Jaundice (hemolytic anemia) + N 0 + Hepatic (cirrhosis, viral hepatitis) + + Oor+ + Posthepatic (obstructive jaundice) N + + t 124 2. Premature labor or premature rupture Toxicology of membranes (PROM) METHODS a. Premature Delivery - Fetal fibronectin (ffN) 1. Immunoassay ❖ Vagi.nal swab specimen ❖ Protein secreted at boundary of 2. Chromatographic Techniques amniotic sac and uterus a. Thin-Layer Chromatography (TLC) ❖ Negative test indicates preterm ❖ Separates drugs for identification delivery will not occur thus ❖ Urine best specimen for detecting sparing preventative measures drugs (MgSO4) with side effects ❖ Limited sensitivity b. Premature rupture of membranes ❖ Results should be confirmed with (PROM) another method ❖ Vaginal swab specimen b. Mass Spectrophotemtry (MS) as ❖ AmniSure TM detects amniotic fluid detector ❖ After separation & quantitation of PAMG-1 present in cen rico- vagi.nal secretions after rupture of drugs & metabolites by high fetal membranes performance liq. chrom. (HPLC or LC) or Gas Chrumatog. (GC) 3. Fetal newborn screening c. Gas Chromatography-Mass a. Dried blood spot specimen Spectrophotometry ( GC-MS) ❖ 11 b. Tandem mass spectrometry used to Gold-standard 11 technique for screen for >25 genetic diseases (ex. confirmation of SCI'eening methods PKU, congenital hypothyroidism, ❖ Highly sensitive and reliable cystic fibrosis, sickle cell disease. ACUTE POISONING other metabolic diseases) - 1. Substances a. Cyanide REMEMBER! h. Carbon monoxide- forms carhoxyhemoglohin ( affinity for ~ Hgb is 200 times the affinity for 0 2) c , Alcohols - Ethanol most common, Hemolytic Disease. of enzymatic - alcohol dehydrogenase d. Heavy meta]s (arsenic, mercury and the Newborn ( HDN). lead) Sin